I adore summertime adventures with my girls, but they do require me to up my diaper bag game in a pretty serious way. In the winter, you can kind of get by with a back-up onesie, the diaper changing basics, and some snacks. But once Memorial Day hits, you suddenly have to consider including things like bathing suits, swim diapers, sun screen, sun hats, bug spray, and more. It's easy to run out of room... and patience! So what are the must-have things to pack in your diaper bag this summer?

First of all, if you're not already rocking a backpack diaper bag, let me try to convert you. My first two diaper bags were the regular messenger style, and I found them impossibly clunky. Trying to push a stroller with an over-stuffed diaper bag clanging against your hip is not fun. Then my sister-in-law turned me on to the backpack idea and it's kind of life-changing. She uses the HapTim Multi-functional Baby Diaper Bag Backpack ($43, Amazon), but I went with my favorite backpack brand, Hershel, which doesn't technically even make diaper bags but does have plenty of options with interior pockets to get the job done. I've also heard good things about the HaloVa Diaper Bag Travel Backpack ($36, Amazon).

So, what do you absolutely need in your diaper bag this summer — whether it's a backpack or not? Here the 5 items I don't leave the house without.

Sun Hat with UV-protection

It can be insanely hard to get an adequate coat of sunscreen on the face of a squirmy infant or toddler, especially since you know you're always just one swipe away from getting SPF in their eyes. That's why it's so helpful to have a reliable sun hat made with UPF 50+ fabric, like this one from iPlay, available in 8 different colors. H&M also has some cute UFP sun caps for babies and kids.

Children's Sunscreen

If your baby is older than 6 months of age, you should be vigilantly applying a sunscreen with at least a 15 SPF, every two hours, according to Mayo Clinic. You'll also want to look for ones that contain titanium dioxide and/or zinc oxide, which provide sun protection while still being gentle enough for a baby's skin, explained the same Mayo Clinic article.

Bug Spray

When I read the statement put out by the Centers for Disease Control (CDC) warning that the spread of contagious diseases by insects is on the rise, I knew that I needed to get serious about bug spray. The statistics are alarming — incidents of diseasesfrom tick, mosquito or flea bites have tripled from 2004 to 2016, according to the CDC statement in May.

If you're wondering if bug spray with DEET is safe for kids, the answer is yes, but with caution. "The [American Academy of Pediatrics] recommends that repellents should contain no more than 30% DEET when used on children. Insect repellents also are not recommended for children younger th​an 2 months," explained Healthychildren.org.

Monkey Mat

Whether you're headed to the beach or to the park, having a water-resistant blanket for you and your little one to comfortably sit on is key. But when you already have a stuffed diaper bag, cramming in a big blanket doesn't always work. That's why I love the Monkey Mat, a Shark Tank product, that folds up into a ultra-compact pouch. Plus, when those inevitable spills happen, the nylon mat is easy to clean.

I'm a huge fan of the Fogo thermos for my girls. It really does keep liquids cold and it's pretty good at not spilling all over thanks to the straw top. If your bambino isn't doing straws yet, Pure Kiki stainless steel bottles ($18, Amazon), with the optional sipper cup spout, are a good bet.